Wonderfully, actively dumb in an Ed Wood way, Zontar was a much more fun sci-fi experience than the same year's Queen of Blood. This is how cheap this movie is: for most of its running time, you don't see the monster. Not for any Jaws-type reasons, but because Keith Ritchie (Tony Huston, below) communicates with it through a big CB radio. Zontar sounds like static, so Keith constantly has to repeat and explain things. The cave "is over a hot spring so it should be somewhat compatible with your Venus environment" and the like. This is magical.
Zontar is here to conquer Earth through the use of what appear to be kindergarten art class versions of tiny Gaoses. Each Gaos affixes a tag to its target, allowing Zontar to control their minds. Keith is super-excited about all this (as you can see) because it will mean an end to Earth's wars and political problems and what have you. His science friend Dr. Curt Taylor (poor John Agar) is less enthused. And Keith's wife (Pat Delaney) is also Team No-Zontar and shrewishly snaps at him in a Southern accent throughout this movie's entire running time.
This movie is endlessly inept and endlessly entertaining. It's also one of the few examples of what you might call small-space apocalypse movies. We're told that Zontar's attack on the world has rendered almost all technology useless, but we're shown this by watching ten or so people over the course of several city blocks. Zontar's global aspirations get channeled into a teeny tiny funnel of characters here.
Some of the choices made by the screenwriter defy comprehension. The big reveal of water coming out of a hose. The comic-relief soldiers ("I sawr a boid!") with corny sitcom music, which incredibly turns into menacing corny sitcom music when one of them finally meets Zontar. Scientists in a three-person lab randomly push buttons. One is such a bad actor that it's tough to tell when he is supposed to be mind-controlled.
Also, if you get bored with the movie proper, you can entertain yourself by staring at the "art" on display at Keith's house. What the hell is that?
Oh, yeah, and this is Zontar.